Low pressure die casting apparatus

ABSTRACT

A low pressure die casting apparatus has one or more furnaces each with a feed duct through the cover, through which molten metal is forced by gas pressure. A die placed in co-operation with a feed duct thereby receives a charge of metal. The entire die mounting structure is arranged to be movable relative to the or each furnace in separate vertical and horizontal modes so that a die can be raised clear and to one side of an associated furnace. The die mounting structure and/or furnace may be movable and the horizontal motion is conveniently made by pivoting about a vertical axis.

United States Patent [191 Cook et al.

[ LOW PRESSURE DIE CASTING APPARATUS [75] Inventors: William JosephCook, Greenford;

Jon Erik Marius Carlsen, Newport, both of England 73 Assignee: DIMOHoldings Limited of Llandowlais Works, Cumbran,

Monmouthshire, England 22 Filed: July 3, 1972 [21] Appl. No.: 268,903

[30] Foreign Application Priority Data July 1, 1971 Great Britain30847/71 [52] US. Cl....'.- 164/306, 164/323 [51] Int. Cl 322d 17/06[58] Field of Search 164/119, 129, 130, 136, 164/306, 323

[ 56] References Cited UNITED STATES PATENTS 3,410,332 11/1968 Woodburnet a1 164/306 X 8/1958 Sylvester 164/119 3,804,152 Apr. 16, 1974 FOREIGNPATENTS OR APPLICATIONS 1,238,700 7/1971 Great Britain 164/306 1,949,5208/1970 Germany 164/136 2,037,652 4/1971 Germany.... 164/119 644,1947/1962 Canada ..164/306 81,646 1/1919 Germany 164/119 PrimaryExaminer-J. Spencer Overholser Assistant Examiner-John E RoethelAttorney, Agent, or Firm-Young and Thompson [5 7] ABSTRACT A lowpressure die casting apparatus has one or more furnaces each with a feedduct through the cover,

through which molten metal is forced by gas pressure.

A die placed in co-operation with a feed duct thereby receives a chargeof metal. The entire die mounting structure is arranged to be movablerelative to the or.

each furnace in separate vertical and horizontal modes so that a die canbe raised clear and to one side of an associated fumace.- The diemounting structure and/or furnace may be movable and the horizontalmotion is conveniently made by pivoting about a vertical axis.

15 Claims, 8 Drawing Figures PATENTEDAPR 16 m4 SHEET 2 [1F 4 PATENTEU P1 5 SHEET 3 OF 4 LOW PRESSURE DIE CASTING APPARATUS This inventionrelates to metal casting apparatus and in particular to a structure formounting a die or die assembly on a furnace of a low pressure diecasting apparatus.

It has been proposed in our British Pat. No. 1,238,700 to provide a diemounting structure for a low pressure die casting apparatus in which theplatens carrying the die parts can be pivoted about a vertical axis awayfrom over the furnace. However, there is still some supporting structureremaining over the furnace, restricting access, and the platens'can onlyco-operate with one furnace and vice-versa.

It is an objectof this invention to provide a die supporting structurewhich can be mounted independently of a furnace and which can bewithdrawn completely clear of the furnace with which it is arranged tooperate. It is a further object of some forms of the invention toprovide a die supporting structure which can be used in conjunction withmore than a single furnace and one which can support more than a singlepair of platens that can be used alternately or in conjunction withseveral furnaces at a time.

According to the present invention there is provided a low pressure diecasting apparatus comprising a furnace and a die supporting structurefor holding a die over the furnace in co-operation with a feed duct fromthe cover thereof, the furnace and the entire die sup,- portingstructure being capable of relative disengagement at least laterally,the lateral movement being substantially independent of any furtherdisengaging action.

This disengagement facility may be achieved in several ways. Inpreferred forms the furnace is fixed and the die supportingstructure isvertically and laterally movable. This is conveniently effected bypivotally mounting the structure on a vertical column laterally offsetfrom the furnace,so that the dies can be swung from over the furnace toa position clear of the latter. The column itself may be movablevertically, by means of a supporting jackfor example, to raise and lowerthe die supporting structure.

vIn its simplest form the die supporting structure includes a singleplaten unit, i.e., one pair of upper and lower platens on whichrespective die parts are mounted and which close together for the actualcasting (over the furnace) and separate for release of the cast article,which, in .this case may be laterally clear of the furnace. In preferredmodified forms the structure may include a plurality of laterallyseparate platen units. With this arrangement, while one platen unit isco-operating with the furnace the or each other platen unit is laterallyclear of the furnace. Thus while one article is being cast another isbeing removed from its die, and the furnace is more continuously in use:

Alternatively there can be provided at least one fur- .ther furnace,vertically and horizontally fixed as the first mentioned furnace, andsimilarly co-operable with and disengageable from the die supportingstructure. With a die supporting structure having a single platen unit,the latter may be selectively brought into engagement with either oranyof the furnaces and have an intermediate position laterally clear ofsaid furnaces. Thus ,while one furnace is being recharged or repairedthe other can be used. With two or more platen units there arepreferably the same number as there are furnaces and either they allco-operate simultaneously or while one platen unit is disposed over itsassociated furnace the other, or at least-one other, is laterally clearof its associated furnace. I

It would be possible to have the die supporting structure fixed and thefurnace or furnaces movable or even have both movable, for example thefurnaces for a short distance vertically and the die supportingstructure horizontally.

In a preferred construction the die supporting structure is in the formof a frame with vertical guide columns extending between upper and lowerplate members. An upper, movable platen is slidable on the columnsbetween the upper and lower plate members, and the latter may serve as,or support, a fixed lower platen. The upper and lower plate members havelateral extensions fixed to the vertical column supported beside thefurnace. The column can rotate about its vertical axis and is verticallymovable, by means of a hydraulic jack for example. Means, such as apneumatic or hydraulic ram, for actuating the upper platen arepreferably mounted on the upper plate member and one or more piston rodsproject down through the upper plate memthrough the duct and nozzle intothe die. The movable platen, carrying on its underside a half-die tocooperate with another half-die on the lower platen is moved into alowered position for casting in synchronism. with the molten metalinjections and is subsequently raised, carrying the cast article, whichis cleared in known manner.

For changing the dies or other operations on the frame or furnace whereit is inconvenient for the frame to be over the furnace, the jack isoperated to raise the vertical column and with it the upper and lowerplate members acting as cantilever arms carrying the whole frame. Thisbrings the lower part of the frame clear of the feed duct and it canthen be pivoted with the column about the latters axis clear of thefurnace. The whole die can then be replaced without anyone having towork over the furnace.

It is preferred to use this construction for large structures, whereasthe version described in British Pat. No. l,238,700 is considered moresuitable for smaller structures.

The invention may be performed in various ways and some constructionalforms thereof will now be described, by way of example, with referenceto the accompanying drawings, in which:

FIG. 1 is a part sectional elevation of a die mounting structure inconjunction with a furnace,

FIG. 2 is a diagrammaic plan view of the structure of FIG. 1,

FIGS. 3 to 6 are diagrammatic plan' views of other die mountingstructures and furnace arrangements according to the invention;

FIG. 7 is a part sectional elevation of the arrangement of FIG. 6, and

.FIG. 8 is a part sectional elevation of a further die mountingstructure and furnace.

The die mounting structure of FIG. 1 has a base 1 on which is mounted afurnace 2. This may be of conventional design and will not be describedfurther. Beside the furnace is a pillar 3 upstanding from the base 1 andguiding by means of brackets 4 a vertical column 5 whose lower end issupported by a jack 6. The column 5 can be raised and lowered to alimited extent by this jack and can rotate about its vertical axis.

A frame generally designated7 is supported by this column 5 and can bepositioned, as shown in full lines in FIG. 2, over the furnace 2, or toone side of the furnace 2 as shown in dotted lines in FIG. 2.

The frame 7 comprises a lower plate 8 and an upper plate 9 bothsubstantially rectangular and between which extend vertical guide rods10. The plates 8 and 9 are held rigidly spaced apart and havere-inforced lateral extensions 8a and 9a respectively whose ends areformed as bosses in which the vertical column 5 enters and is fixed. Theframe thus rotates with the column 5 arms supporting the whole frame. Anupper platen 11 slides on the guide rods and is actuated by means of ahydraulic or pneumatic cylinder 12 mounted on the upper plate 9. Thispiston rod 13 of this cylinder extends vertically downwards through theupper plate 9 to connect with the platen 11. The lower plate 8 may serveas a fixed lower platen or have a further platen securely mountedthereon. The upper platen has a range of movement as illustrated betweenthe full and dotted line positions.

For use, an upper die member (not shown) is fixed to the underside ofthe movable platen 11 and a lower die member (also not shown) is fixedon the lower platen 8 and a die setting operation is carried out. A feedduct 14 extends through an opening in the top plate 15 of the furnaceand when the frame 7 is swung over the furnace and lowered into anoperative position bythe jack 6, the feed duct co-operates with a nozzle16 leading to the lower half-die. The half-dies are moved repeatedlytogether and in synchronism with.

this molten metal is moved-by gas from the melting pot to the diesupported in the die mounting structure. When the upper half-die israised the cast article is carried with it in known manner and removedby conventional means.

The devices for supplying gas under pressure to the furnace and themelting pot may be conventionally arranged and are not shown.

Whenthe die mounting structure provided by the frame is to be moved tothe inoperative position from over the furnace 2 the frame 7 is simplyraised by actuation of the jack 6 to break the connection between feedduct and nozzle and it is then free to swing to that new position. 1

It will be understood that instead of fixing the frame to the column 5the bosses may be such as to allow the frame to rotate on the column,which need then only be vertically movable.

In FIGS. 3 to 6 are illustrated in diagrammatic plan view modified diemounting structures and/or modified furnace arrangements. Similarreferences, with indices where necessary when parts are duplicated,indicate similar parts.

IN FIG. 3, the base 1, furnace 2 and supporting pillar 3 are the same,but the die mounting structure comprises two frames 7 and 7 setsubstantially at right angles. They are rigidly interconnected by webs8b (not visible) and 9b corresponding to the extensions 8a and 9a. Thuseither frame 7 or 7 can be set over the single furnace 2 for diecasting, while the other frame is swung to one side. In the figure, theframe 7 is moved to the left hand side when inoperative and the frame 7"to the right hand side. With some castings it may be convenient to usethe frames in alternation, so that while one article is being cast,another is being removed well clear of the furnace.

In FIG. 4 a column 5 is supported in similar manner between two furnaces2 and 2" but carries a single frame 7. This can be swung throughsubstantially a 1 arc to co-operate with either furnace as desired. Inan intermediate position the frame is clear of both furnaces. Thisapparatus can be used like the one of FIGS. 1 and 2, with the.beneficial addition of a reserve furnace which can be serviced andrecharged while the other is operating.

FIG. 5 is in effect a combination of FIGS. 3 and 4, having'two furnaces2' and 2" and two frames 7 and 7" pivotally supported from a column 5between the furnaces. The frames being set substantially at right anglescan co-operate alternately with the furnaces, frame 7' with furnace 2'(as shown) and frame 7" with furnace 2".

In the apparatus so far described, the pivoting movement is onlysemi-rotary (through approximately or I80") and the die supportingstructure being entirely to one side of the supporting column requiresthat column to have massive support. A balanced arrangement is showninFIG. 6 with symmetrically opposed furnaces 2" and frames 7". Here theframes will co-operate simultaneously with the furnaces and be movedclear together. A preferred form of column for this arrangement is shownin FIG. 7. i

The column of FIG. 7 comprises a fixed vertical pillar 17 having anaxial bore 18 forming an oil duct, the inlet 19 to which is radial nearthe base of the column. The duct 18 opens into a cylindrical recess 20at the top of the pillar 17 which houses a vertically movable piston 21.The piston rod 22 extends upwardly through an end cap 23 to terminate ina thrust bearing 24 which rotatably supports a sleeve 25 by engaging anupper end plate 26 thereof. The sleeve embraces the upper part of thepillar l7 and the interconnecting webs 8c and 9c between the frames,through the centres of which the sleeve is entered, are welded orotherwise secured thereto. Thus the frames 7" and sleeve 25 can pivotthrough a full 360 about the fixed pillar l7 and can be raised andlowered by the hydraulic jack built-into the top of the pillar.

It will be understood that there could be more than two furnaces and/ormore than two die supporting frames pivoted on a common column, thefurnaces for example being set in an annular or part annular array withthe column at the centre, the radius of the array being such as to allowclear spaces between adjacent furnaces in which to registernon-operative die structures. Further possible arrangements are a lineararray of furnaces with intermediate columns each carrying single platenunits (as of FIGS. 1, 2 and 4), an L-shaped die supporting structure (asof FIGS. 3 and S) or a balance d die supporting structure (as of FIG.6). Except for the end ones, the furnaces can then each be served by twoseparate die structures.

In FIG. 8 there is illustrated apparatus similar to FIG. 7 but with theadditional facility of the furnaces, only one of which is shown, beingrotatable about the central column. When use is made of this facilitythe die supporting structure can be rendered non-rotatable by lockingpegs 27 entered through the sleeve 25 and engaging in axially parallelgrooves 28 in the pillar 17. These grooves allow the sleeve and diestructure to be raised and lowered as before.

The furnaces 7" are mounted on a turntable 29 which can rotate about aheightened base 30 of the pillar 17. The outer periphery of theturntable 29 is fitted on the underside with rollers or wheels 31 thatrun on an annular track 32 centred on the pillar axis and a rollerbearing 33 is provided between the base 30 and the surrounding innerperiphery of the turntable.

It will be understood that the other embodiments described can alsoreadily be modified to have rotary furnaces, although not through thefull 360 as with the balanced arrangement. Also, it is not essential tohave the die supporting structure rotatable when the furnaces can be somoved.

It is furthermore possible in each case to give the vertical movement tothe furnaces instead of or in addition to the die supporting structure.For this, the furnaces may be supported by jacks.

The rotary movement for all embodiments may be motorised, although inmost cases it will be practical to swing the die structure and/orfurnaces by hand. It will also often be convenient to provide stops forarresting the die structures and furnaces in correct vertical registry.

Instead of pivoting the die supporting structures, or rotating thefurnaces, they may be arranged to move in another mode, for example onrails or other linear guides, the die structures to and from a singlefurnace, or along a row of spaced furnaces and the furnaces below asingle die structure or beneath a row of spaced die structures.

We claim:

1. A low pressure die casting apparatus comprising a furnace, agenerally vertical feed duct from the cover thereof, and a diesupporting structure for holding a die over the furnace in co-operationwith said feed duct, wherein the improvementcomprises a first mountingfor the furnace and a second mounting for the die supporting structurelaterally clear of and separate from the furnace, and means for movingat least one mounting for vertical engagement and disengagement of thediewith the feed duct and, independently of such vertical movement, forlateral displacement between furnace and die supporting structure in anarc centred on one of said mountings.

2. Apparatus according to claim 1, wherein the first mounting maintainsthe furnace at a fixed level and the second mounting permits the diesupporting structure to be vertically movable.

3. Apparatus according to claim 1, wherein the second mounting maintainsthe die supporting structure at a fixed level and the first mountingpermits the furnace to be vertically movable.

4. Apparatus according to claim 1, wherein the first mounting maintainsthe furnace at a fixed horizontal location and the second mountingpermits the die supporting structure to be laterally movable.

5. Apparatus according to claim 1, wherein the second mounting maintainsthe die supporting structure at a fixed horizontal location and thefirst mounting permits the furnace to be laterally movable.

6. Apparatus according to claim 2, wherein the second mounting includesa vertical column whose axis is the pivot axis for the lateraldisplacement and which is vertically movable to raiseand lower saidstructure.

7. Apparatus according to claim 1, and comprising at least one furtherfurnace carried by the first mounting and co-operable with anddisengageable from the die supporting structure, similarly as the firstmentioned furnace.

8. Apparatus according to claim 1, wherein the die supporting structureincludes a single platen unit.

9. Apparatus according to claim 1, wherein the die supporting structureincludes a plurality of laterally separate platen units.

10. Apparatus according to claim 9 wherein said platen units arelaterally stationary within the entire'die supporting structure.

.11. Apparatus according to claim 10, wherein the platen units arearranged in the die supporting structure so that when one platen unit isco-operating with the furnace another platen unit is laterally clear ofthe furnace. v

12. Apparatus according to claim 7, wherein the die supporting structureincludes a single platen unit selectively co-operable with any of saidfurnaces, said platen operating with an associated furnace anotherplaten unit is laterally clear of its associated furnace.

15. Apparatus according to claim 13, wherein the furnaces are sodisposed and the arrangement of the platen units is such that all theplaten units co-operate simultaneously with associated furnaces and haveintermediate positions clear of said furnaces.

1. A low pressure die casting apparatus comprising a furnace, agenerally vertical feed duct from the cover thereof, and a diesupporting structure for holding a die over the furnace in cooperationwith said feed duct, wherein the improvement comprises a first mountingfor the furnace and a second mounting for the die supporting structurelaterally clear of and separate from the furnace, and means for movingat least one mounting for vertical engagement and disengagement of thedie with the feed duct and, independently of such vertical movement, forlateral displacement between furnace and die supporting structure in anarc centred on one of said mountings.
 2. Apparatus according to claim 1,wherein the first mounting maintains the furnace at a fixed level andthe second mounting permits the die supporting structure to bevertically movable.
 3. Apparatus according to claim 1, wherein thesecond mounting maintains the die supporting structure at a fixed leveland the first mounting permits the furnace to be vertically movable. 4.Apparatus according to claim 1, wherein the first mounting maintains thefurnace at a fixed horizontal location and the second mounting permitsthe die supporting structure to be laterally movable.
 5. Apparatusaccording to claim 1, wherein the second mounting maintains the diesupporting structure at a fixed horizontal location and the firstmounting permits the furnace to be laterally movable.
 6. Apparatusaccording to claim 2, wherein the second mounting includes a verticalcolumn whose axis is the pivot axis for the lateral displacement andwhich is vertically movable to raise and lower said structure. 7.Apparatus according to claim 1, and comprising at least one furtherfurnace carried by the first mounting and co-operable with anddisengageable from the die supporting structure, similarly as the firstmentioned furnace.
 8. Apparatus according to claim 1, wherein the diesupporting structure includes a single platen unit.
 9. Apparatusaccording to claim 1, wherein the die supporting structure includes aplurality of laterally separate platen units.
 10. Apparatus according toclaim 9, wherein said platen units are laterally stationary within theentire die supporting structure.
 11. Apparatus according to claim 10,wherein the platen units are arranged in the die supporting structure sothat when one platen unit is co-operating with the furnace anotherplaten unit is laterally clear of the furnace.
 12. Apparatus accordingto claim 7, wherein the die supporting structure includes a singleplaten unit selectively co-operable with any of said furnaces, saidplaten unit having at least one intermediate position laterally clear ofsaid furnaces.
 13. Apparatus according to claim 7, wherein the diesupporting structure includes a plurality of laterally separate platenunits and there are the same number oF furnaces as there are platenunits.
 14. Apparatus according to claim 13, wherein the furnaces are sodisposed and the arrangement of the platen units is such that when anyone platen unit is co-operating with an associated furnace anotherplaten unit is laterally clear of its associated furnace.
 15. Apparatusaccording to claim 13, wherein the furnaces are so disposed and thearrangement of the platen units is such that all the platen unitsco-operate simultaneously with associated furnaces and have intermediatepositions clear of said furnaces.